Tilt-out frame for a filter screen

ABSTRACT

A filter screen that is used in filtering water and that includes a frame and a grid assembly that is supported by the frame for movement. The grid assembly includes a continuous unbroken drive chain having a guide link, and a screen panel. The screen panel is coupled to the guide link for selective movement between an operating condition and a maintenance condition. When the screen panel is in the operating condition the screen panel is fixed relative to the guide link for movement with the guide link and for filtering water. In the maintenance condition, the screen panel is pivotable relative to the guide link to permit access to the interior of the filter screen for inspection of chain components.

FIELD OF THE INVENTION

[0001] The invention relates to filter screens, and more particularly tofilter screens having screen panels.

BACKGROUND OF THE INVENTION

[0002] Wastewater and water treatment plants utilize filter screens toremove harmful debris from channeled water. The filter screen istypically utilized in the first area to come in contact with thechanneled water. In order to protect downstream equipment and processes,the filter screen removes debris before it comes into contact with anydownstream equipment.

[0003] One type of filter screen includes a grid assembly and a drivesystem to move and rotate the grid assembly. The drive system includesan endless chain, and a plurality of screen panels that are connected tothe chain. The screen panels generally include a frame and filterinserts that are supported by the frame.

[0004] The movement of the chain and screen panels result in wear of thechain and its components. Prior art screens do not facilitate inspectionof the chain and its components. The prior art designs require that thechain and screen panel assemblies be completely disassembled from thechain and removed from the filter screen for either inspection orreplacement of chain components. In the prior art arrangements, when theframes and chains are disassembled, the chain becomes unsupported andclamps are required to hold all the components in place while theinspection or the replacement of chain components takes place.

[0005] The filter screens remove debris from the water when the water ischanneled from the interior of the grid assembly to the exterior of thegrid assembly through the bottom and sides of the grid assembly. Debriscommonly becomes trapped on the interior side of the filter screens andmust be manually removed to ensure proper operation. Known gridassemblies do not facilitate access to the interior of the gridassembly. These designs require the chain to be separated and the filterscreen to be removed to gain access to the interior of the grid assemblyfor the removal of trapped debris.

SUMMARY OF THE INVENTION

[0006] The present invention is directed to a filter screen thatsimplifies inspection and maintenance of the grid assembly by providingpivoting screen panels. The screen panels are coupled to the chain forselective pivoting movement such that the screen panel can be pivotedrelative to the chain for repair and/or inspection without completelyremoving the screen panels from the chain. The screen panels alsoprovide access to the chain components and the interior of the gridassembly while maintaining continuous connection of the chain.

[0007] One embodiment of the present invention is directed to a filterscreen for use in filtering water. The filter screen includes a frameand a grid assembly that is supported by the frame for movement. Thegrid assembly includes a continuous unbroken drive chain having a guidelink, and a screen panel. The screen panel is coupled to the guide linkfor selective movement between an operating condition and a maintenancecondition. When the screen panel is in the operating condition thescreen panel is fixed relative to the guide link for movement with theguide link and for filtering water. In the maintenance condition, thescreen panel is pivotable relative to the guide link to permit access tothe interior of the filter screen for inspection of chain components.

[0008] Another embodiment of the invention is directed to a gridassembly for use in a filter screen to filter water. The grid assemblyincludes a continuous unbroken drive chain having a guide link, and ascreen panel. The screen panel is coupled to the guide link forselective movement between an operating condition and a maintenancecondition. When the screen panel is in the operating condition thescreen panel is fixed relative to the guide link for movement with theguide link and for filtering water. In the maintenance condition, thescreen panel is pivotable relative to the guide link to permit access tothe interior of the filter screen for inspection of chain components.

[0009] Other features and advantages of the invention will becomeapparent to those skilled in the art upon review of the followingdetailed description, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a side elevation view illustrating a filter screenembodying the present invention.

[0011]FIG. 2 is a perspective view illustrating a drive system and agrid assembly of the filter screen shown in FIG. 1.

[0012]FIG. 3 is a perspective view of the grid assembly shown in FIG. 2,illustrating a screen panel in a maintenance condition.

[0013]FIG. 4 is a front view illustrating the screen panel shown in FIG.3.

[0014]FIG. 5 is a side view illustrating the screen panel shown in FIG.4.

[0015] FIGS. 6-8 are side views of a portion of the grid assembly shownin FIG. 2, illustrating the conversion of the screen panel from the anoperating condition to the maintenance condition.

[0016] Before one embodiment of the invention is explained in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangements of the componentsset forth in the following description or illustrated in the drawings.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways. Also, it is understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including” and “comprising” and variations thereof herein is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items. The use of “consisting of” and variations thereofherein is meant to encompass only the items listed thereafter. The useof letters to identify elements of a method or process is simply foridentification and is not meant to indicate that the elements should beperformed in a particular order.

DETAILED DESCRIPTION

[0017]FIG. 1 illustrates a continuous self-cleaning filter screen 10that is used in wastewater and water treatment plants to remove debristhat is contained in channeled water 12. In order to protect downstreamequipment processes, the filter screen 10 is designed to remove a largemajority of the debris before it comes into contact with any downstreamequipment. With further reference to FIG. 2, the filter screen 10includes a frame 14, a drive system 16 rotatably mounted to the frame14, and a grid assembly 18 that is driven by the drive system 16.

[0018] The filter screen 10 provides for flow of the channeled water 12into the center of the grid assembly 18 and then exit out the bottom andsides of the grid assembly 18. The filter screen 10 removes the debrisfrom the channeled water 12, and also dewaters and compacts the removeddebris with an integral screw compactor 20.

[0019] The drive system 16 includes a drive shaft 22 and first andsecond drive sprockets 24 coupled for rotation with the drive shaft 22.The drive sprockets 24 engage the grid assembly 18 such that rotation ofthe drive shaft 22 by a motor (not shown) causes the drive sprockets 24to move and rotate the grid assembly 18.

[0020] The grid assembly 18 includes first and second continuous drivechains 26. Each drive chain 26 includes a corresponding plurality ofinterconnected non-metallic guide links 28. Each guide link 28 includesa first portion 30 and an opposite second portion 32. The first portion30 of each guide link 28 is rotatably coupled to a second portion 32 ofan adjacent guide link 28 about a moveable pivot axis 34 to form anenclosed loop. Each guide link 28 includes a bearing surface 36 thatengages a tracking system (not shown) of the frame 14 such that thebearing surfaces 36 of the guide links 28 slide around the trackingsystem as the drive chain 26 is moved by the drive sprocket 24. The gridassembly 18 also includes wear bushings 38 that are each centered abouta respective pivot axis 34 and that project inwardly from the guidelinks 28 (FIG. 3).

[0021] As best shown in FIG. 3, each drive chain 26 also includes sealplates 40 that are coupled to the inside of the guide links 28. Eachseal plate 40 is coupled to a respective guide link 28 such that theseal plate 40 rotates with the guide link 28 relative to the adjacentguide link 28 about the pivot axis 34. Each seal plate 40 projects pastthe bearing surface 36 of the respective guide link 28 to preventoutward lateral movement of the drive chain 26. The seal plates 40 onboth drive chains 26 combine to maintain the drive chains 26 on thetracking system of the frame 14.

[0022] Referring again to FIG. 2, the grid assembly 18 includes aplurality of screen panels 42 that corresponds to the number of guidelinks 28. With additional reference to FIG. 4, each screen panel 42includes a frame 44 having an upper member 46, a lower member 48, andend members 50 that connect the ends of the upper and lower members 46,48. The frame 44 is preferably metallic and defines an enclosed space52. The frame 44 includes a plurality of cross members 54 within theenclosed space 52 that connect the upper and lower members 46, 48 atintermediate locations along the upper and lower members 46, 48. Theplurality of cross members 54 divide the enclosed space 52 of the frame44 into four equally-sized sections 56.

[0023] An insert panel 58 is supported within each of the sections 56 tofilter debris from the channeled water 12. The insert panels 58 aremolded from a high strength plastic and are easily removed and replacedfrom the individual sections 56. The insert panels 58 include elongatedfiltering members 60 that are equally spaced from each other across theinsert panel 58. When different filtering capabilities are required bythe filter screen 10 the insert panels 58 are replaced with insertpanels 58 that include different sized spacing between the filteringmembers 60.

[0024] The frame 44 of the screen panel 42 is not required to befabricated from metal. Rather, the frame 44 can be made from anon-metallic material such as a high strength plastic without departingfrom the scope of the present invention. Additionally, the frame 44 andthe insert panels 58 can be integrally molded as a single piece screenpanel 42.

[0025] As best shown in FIG. 4, the end members 50 include a firstportion 62 that is connected to the upper member 46 and a second portion64 that is connected to the lower member 48. Each end member 50 includesa hook 66 that is adjacent to the first portion 62 and a slot 68 that islocated near the second portion 64. The slot 68 includes a longitudinalaxis 70 that is parallel to a longitudinal axis 72 of the end member 50.Each end member 50 also includes a hole 74 between the hook 66 and theslot 68.

[0026]FIG. 6 illustrates a portion of the grid assembly 18 with top,center, and bottom screen panels 42A, 42B, 42C in operating conditions.In the operating condition, the screen panels 42 are fixed relative to arespective guide link 28 for movement with the guide link 28 around thetracking system and for filtering contaminates from the channeled water12. The end members 50 of the frames 44 are connected to the respectiveguide links 28 and seal plates 40 by first and second fasteners 76, 78such that the hook 66 engages the bushing 38. The first fastener 76extends through the hole 74 in the end member 50 and through acorresponding set of aligned holes 80 in the guide link 42 and sealplate 40. The second fastener 78 extends through the slot 68 in the endmember 50 and through another set of aligned holes 82 in the guide link28 and seal plate 40.

[0027] The conversion of the screen panel 42 from the operatingcondition to a maintenance condition will be described with reference tothe center screen panel 42B in FIGS. 6-8. In the maintenance condition,the screen panel 42B is moveable relative to the guide link 28 and sealplate 40 to allow access to the bushings 38 for repair and replacement.As shown in FIG. 6, the first fastener 76 is removed from the guide link28, the seal plate 40, and the end member 50. In addition, the secondfastener 78 is loosened such that the screen panel 42B is free to movein the longitudinal direction of the end members 50.

[0028] As shown in FIG. 7, the screen panel 42B is raised relative tothe guide link 28 and seal plate 40 such that the slot 68 moves relativeto the loosened second fastener 78 and the hook 66 disengages from thebushing 38.

[0029] Referring to FIG. 8, after the screen panel 42B is raised and thehook 66 disengages from the bushing 38, the screen panel 42B is allowedto pivot relative to the guide link 28 and seal plate 40 about thesecond fastener 78.

[0030] Referring back to FIG. 3, when the screen panel 42 is located inthe maintenance condition the bushings 38 are accessible for visuallyinspecting wear and for removing and replacing a worn bushing 38 orother chain components. In addition, when the screen panel 42 is in themaintenance condition, the drive chains 26 are not disconnected, andtherefore no special equipment is necessary to maintain the drive chains26 in continuous loops.

[0031] The screen panel 42 is returned to the operating condition fromthe maintenance condition by pivoting the screen panel 42 upward intoalignment with the guide link 28 and the seal plate 40 such that thehook 66 re-engages the bushing 38. The first fastener 76 is thenre-inserted into the hole 74 of the end member 50 and the holes 80 inthe guide link 28 and the seal plate 40, and the first and secondfasteners 76, 78 are tightened to fasten the screen panel 42 to theguide link 28 and seal plate 40.

We claim:
 1. A filter screen for use in filtering water, the filterscreen comprising: a frame; a grid assembly supported by the frame formovement, the grid assembly including a continuous unbroken drive chainhaving a guide link, and a screen panel coupled to the guide link forselective movement between an operating condition where the screen panelis fixed relative to the guide link for movement with the guide link andfor filtering water and a maintenance condition where the screen panelis pivotable relative to the guide link to permit access to the filterscreen.
 2. The filter screen of claim 1, wherein the grid assemblyfurther includes an additional continuous unbroken drive chain having aguide link, wherein the screen panel is coupled to the guide link of theadditional drive chain for selective movement between the operatingcondition where the screen panel is fixed relative to the guide link ofthe additional drive chain for movement with the guide link of theadditional drive chain and for filtering water and the maintenancecondition where the screen panel is pivotable relative to the guide linkof the additional drive chain to permit access to the filter screen. 3.The filter screen of claim 1, wherein the grid assembly further includesa bushing coupled to the guide link, wherein the screen panel includesan end member having a hook that engages the bushing in the operatingcondition and that disengages from the bushing in the maintenancecondition.
 4. The filter screen of claim 3, wherein the screen panelmoves linearly relative to the guide link to disengage the hook from thebushing in the maintenance condition.
 5. The filter screen of claim 4,wherein the guide link includes a projection, and wherein the end memberincludes a slot having a longitudinal axis, the projection beingpositioned within the slot such that the screen panel pivots about theprojection and moves linearly along the slot axis in the maintenancecondition.
 6. The filter screen of claim 5, wherein the guide linkincludes a hole, and wherein the projection is a fastener positioned inthe hole of the guide link.
 7. The filter screen of claim 5, furthercomprising a fastener that couples the guide link and the screen paneltogether in the operating condition.
 8. The filter screen of claim 7,wherein the guide link includes a hole, and the end member includes ahole, the fastener being positioned in the hole of the guide link andthe hole of the end member in the operating condition.
 9. The filterscreen of claim 8, wherein the hole of the end member is positionedbetween the slot and the hook.
 10. A grid assembly for use in a filterscreen to filter water, the grid assembly comprising: a continuousunbroken drive chain including a guide link; a screen panel coupled tothe guide link for selective movement between an operating conditionwhere the screen panel is fixed relative to the guide link for movementwith the guide link and for filtering water and a maintenance conditionwhere the screen panel is pivotable relative to the guide link to permitaccess to the filter screen.
 11. The grid assembly of claim 10, furthercomprising an additional continuous unbroken drive chain including aguide link, wherein the screen panel is coupled to the guide link of theadditional drive chain for selective movement between the operatingcondition where the screen panel is fixed relative to the guide link ofthe additional drive chain for movement with the guide link of theadditional drive chain and for filtering water and the maintenancecondition where the screen panel is pivotable relative to the guide linkof the additional drive chain to permit access to the filter screen. 12.The grid assembly of claim 10, further comprising a bushing coupled tothe guide link, wherein the screen panel includes an end member having ahook that engages the bushing in the operating condition and thatdisengages from the bushing in the maintenance condition.
 13. The gridassembly of claim 12, wherein the screen panel moves linearly relativeto the guide link to disengage the hook from the bushing in themaintenance condition.
 14. The grid assembly of claim 13, wherein theguide link includes a projection, and wherein the end member includes aslot having a longitudinal axis, the projection being positioned withinthe slot such that the screen panel pivots about the projection andmoves linearly along the slot axis in the maintenance condition.
 15. Thegrid assembly of claim 14, wherein the guide link includes a hole, andwherein the projection is a fastener positioned in the hole of the guidelink.
 16. The grid assembly of claim 14, further comprising a fastenerthat couples the guide link and the screen panel together in theoperating condition.
 17. The grid assembly of claim 16, wherein theguide link includes a hole, and the end member includes a hole, thefastener being positioned in the hole of the guide link and the hole ofthe end member in the operating condition.
 18. The grid assembly ofclaim 17, wherein the hole of the end member is positioned between theslot and the hook.